Computing devices and associated computing networks enable users to create, share, and modify electronic files, which are stored on file systems. Access control mechanisms have been implemented to control access to these file systems by certain users or groups of users. These prior access control systems control access of each user to locations, such as volumes or folders, on the file system. In this way, the access control system may prevent an unauthorized user from opening a file that is stored in a location that the user is not authorized to access. One drawback with such an approach is that a file is only protected from unauthorized access so long as it remains in the secure location on the file system. Once the file is copied and moved out of the secure location, for example, if the file is sent as an attachment to an email or saved to a universal serial bus (USB) drive, the security protections are lost and anyone with access to the email or USB drive can open the file. For this reason, some files may be encrypted, however, encryption keys are difficult to manage, particularly when the encrypted data is sent outside an organization for receipt by a third party. As a result, many sensitive files are sent out of organizations in unencrypted form, exposing them to a risk of unauthorized access.